Can you confirm you are using a version of the suite that is compatible with IE10? That is, Q3 2012 and above? Can you reproduce the problem in our demos, e.g. here
(not that many others use RestrictionZone and the RadWindow should not be centered in the screen but in the zone; or there are offsets applied, etc.).
Also, if your site is framed and your page is actually somewhere in an iframe on the page this can offest the control. I can position itself only to the current window object and not to the topmost frame as general browser restrictions do not allow the latter.
Could you also post the simplest code that is not working with you if neither of the above works fine for you so we can actually inspect the problem you are having?
the Telerik team
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